With an increased variety of access networks, customer premises equipment (CPE) and teleconferencing bridges, echo has become a serious problem in providing teleconferencing services. Currently, if there is echo on a teleconference call, participants must go through a painstaking and time-consuming effort to “manually” troubleshoot the source of the echo. That can be very difficult since most people do not fully understand echo and its sources. Further, the person on the line causing the echo cannot hear the echo, compounding the problem.
In many cases, a participant must report echo problems in a teleconference to the teleconferencing service provider, who then must provide support in real time to try to determine where the echo is originating and how best to deal with it. While manual troubleshooting takes place, the substantive work on the teleconference must be halted completely. Depending on the number of participants on the call, that delay can be substantial, resulting in a serious decrease in productivity.
Teleconferencing bridges have multiple ports or legs. Each port or leg typically connects to a single participant. The main function of the teleconference bridge is to mix all speaking participants' voices together, and to play the resulting mixture to all legs. When echo is on one leg, the echo will be mixed and then broadcast to all participants, creating a significant impairment.
The use of voice-over-IP (VoIP) CPEs, mobile phones and speakerphones all increase the probability of echo. In addition, IP teleconferencing bridges are gradually replacing TDM (time division multiplexing) bridges. The switch to IP teleconferencing from TDM teleconferencing results in a significant increase in end-to-end delay. That delay makes any echo significantly more perceptible and disruptive. The impact of the echo problem is greater in teleconferencing than in a regular two party call because the echo is heard by so many participants, and because there are more potential sources of echo in a teleconference call.
Most teleconferencing services depend on local network echo cancellers to control echo. For a variety of reasons, the echo control in the access network is often not adequate. Currently, if there is unacceptable echo in a teleconference, the teleconference participants must spend valuable teleconference time attempting to locate which leg is the source of echo, often with the help of the service provider's customer support.
The current procedure for troubleshooting an echo problem in a teleconference is to ask participants on every leg to mute their lines, then to ask each participant, one at a time, to un-mute his or her line, and then check whether echo is heard by the participants and/or customer support. Once the leg having echo is identified, the participant on that leg is asked either to mute the phone, switch to another handset or re-dial into the conference, hoping to get a better echo control connection. Because a teleconferencing call often includes over 10 or 20 people, that manual diagnostic process is time consuming, costly and inconvenient.
There therefore remains a need for a cost-effective technique to identify and cure a source of echo in a teleconferencing call, while minimizing the above-described disadvantages.